One of the crash test performed to a bumper is the RCAR Allianz Crash Repair test, commonly known as the AZT crash test. In said test the AZT barrier has a mass of 1400 kg, it impacts the bumper of the vehicle with a velocity of 16 km/h and at an impact angle of 10° which often results in an undesired high peak load at the beginning of the load curve when measuring force over time.
An optimal behavior of the bumper in the test would be a constant high load over time, i.e. the cross beam of the bumper should deform and “cushion” the initial peak load before the crash box/boxes of the bumper starts to buckle.